Bifocal-lens-grinding machine.



N0. 640,I9I. Patented Jan. 2, I900.

w. H. GAITHER.

BIFUCAL LENS GRINDING MACHINE.

(Application filed Apr. 21, 1899.)

(No Model.) ,4 Sheets-Sheet l.

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N0. 64D,|9l. v Patented Jan. 2, I900. W. H. GAITHEB.

BIFDCAL LENS GRINDING MACHINE.

(Application filed Apr, 21, 1899.)

4 Sheets-Sheet 2.

(No Model.)

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N0. 640,!9l. Patented Jan. 2., I900. W. H. GAITHER.

BIFOGAL LENS GRINDING MACHINE.

(Application filed Apr. 21, 1899.),

(No Model.) 4 Sheets-Sheet 3.

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J Z I i 1 1g A 4? if 7i Witnesses, m/e 22 to 71- No. 640,191. PatentedJan. 2, I900.

w. u. GAITHER.

BIFOCAL LENS GRINDING MACHINE.

(Application filed Apr. 21, 1899.) (No Model. 4 Sheets$heat 4;

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UNIT D STATES PATENT OFFICE.

IVALLAOE H. GAITHER, OF ERIE, PENNSYLVANIA.

BIFOCAL-LENS-GRINDING. MACHINE.

SPECIFICATION forming part of Letters Patent No. 640,191, dated January2, 1900.

Application filed April 21, 1899- To aZZ whom it may concern:

Be it known that LWALLAOE H. GAITHER, a citizen of the United States,residing at Erie, in the county of Erie and State of Pennsyl Vania, haveinvented certain new and useful Improvements in Bifocal-Lens-GrindingMachines; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, formin g part of this specification.

My invention relates to machines for grinding optical lenses, andparticularly to machines for grinding bifocal lenses; and it consists,substantially, in the construction of mechanism whereby a bifocal lensmay be ground from a single glass, so that the meeting-points of the twofields of the lens are substantially on the same plane, as hereinafterset forth and described, and illustrated in the accompanying drawings,in whieh--- Figure 1 is a view in perspective of a machine embodying myinvention. Fig. 2 is a top or plan view of the same with thecountershaft omitted. Fig. 3 is a side view in elevation of the same.Fig. at is a view in elevation of the adj ustable chuck-plate of mymachine. Fig. 5 is a longitudinal section of a portion of the machine,the section through the chuck-plate being on the line 00 in Figs. 4: and6. Fig. 6 is a vertical sectional view on the line y in Fig. 3. Fig. 7is a front view of a bifocal lens ground on my machine. Fig. 8 isavertical section of the same on the line a in Fig. 7.

In the drawings thus illustrating my invention, A is the bed-plate ofthe machine. Upon the ends of this bed-plate there are standards A A inwhich a rod or bar B is secured, and at one side of the standard A thereare longitudinal ways A ,upon which grinding mechanism D is mounted,adapted to be adjusted back and forth on said ways by a screw 0. Uponthe rod or bar B there are mounted sleeves E and F, secured in place bysetscrews 9 and f and adapted to be adjusted longitudinally on the rodor bar B. The sleeve E, located adjacent to the standard A, is providedwith a downwardly-projecting Serial No. 713,832. (No model.)

arm Gr, provided at its lower end with a socket G, having a ball Gjournaled and rotating freely therein. In the ball G there is secured asleeve H, provided with pulleys h h and driven by belts h and hifrom adrum II on an oscillating counter-shaft H driven by crank mechanism H orin some other convenient manner. On one end of the sleeve H there is aclutch H, by means whereof the sleeve H may be clamped to a shaft I, asclearly shown in Fig. 5. The sleeve F is located adjacent to thegrinding mechanism D and is provided on its lower side with a transversesleeve F, in which a transverse rod J is secured. Upon this rod J thereare mounted two arms J J one at each side of the sleeve F, so as toslide longitudinally and rotate on the rod J, these arms being joined attheir lower ends to the edges of a lenschuck-plate support K, which issupported from the rod J by the arms J J On the portion of the rod Jextending beyond the arm J there is loosely mounted a pulley L, providedwith a sleeve L, the end of which contacts with the outside of the armJ, and.

the rod J is provided with a screw-thread j, extending from the endthereof back into the sleeve L, and against the outside of the pulley Lthere is a circular nut L operating on the thread j. This nut isprovided with grooves Z in its periphery, adapted to engage a reversibledog Z on the pulley L, whereby the nut L may be rotated in unison withthe pulley L in either direction desired. On the opposite end of the rodJ, extending beyond the arm J there is a spiral spring J the innor end jof which contacts with the arm J 2 and its outer end j with a collarj onthe end of the rod J, held in place by a nut 7' Thus the rotation of thenut L on the thread j in one direction operates, through the contact ofthe sleeve L against the outside of the arm J, to move the arms J and Jand the frame K, with the lens-chuck plate and the lenschuck thereon, inone direction on the rod J and in so doing compresses the spring J butwhen the nut L is rotated in the opposite direction the spring Joperating against the outside of the arm J moves the arms J J and thechuck-plate support K in the opposite direction on the rod J. Thus inthis manner the lateral movement of the chucksupporting frame K and thechuck therein is accomplished. The pulley 'L is driven by means of abelt Z from a pulley H on the counter-shaft 1-1 The chuck-support K ismade in the form of a separable annular ring, the inner surface k ofwhich is concave. The chuck-plate M is provided with arearwardlyprojecting flange N, the outer surface n of which is convexand is mounted within the concave surface of the lens-chuck support K soas to move freely therein. The shaft I is connected to the back of thechuck-plate M by means of a yoke I on the end of the shaft I, which yokeI is connected to the back of the chuck-plate M by means of screws ti,passing through slotted holes m m in the chuck-plate M at some distanceto one side of the center of the chuck-plate M, as clearly shown in Fig.4, the slotted holes m m in the plate M enabling the yoke I to beadjusted toward and away from the axis of the plate M. The chuck O isprovided with a rearwardly projecting central stud 0, passing through ahole m at the intersection of the line 00 with a line m passing throughthe plate M at right angles to the line 00, as illus trated in Figs. 4,5, and 6, where it is engaged by clamping-jaws o 0', and on the back ofthe chuck 0 there is a stud 0 adapted to enter a hole in the face of theplate M, so that the chuck 0 will not rotate on the stud 0. To the faceof the chuck O the glass P to be ground is cemented or secured in theusual manner. It will be observed that as the chuck'plate M isoscillated back and forth it has a gyratin g motion in the chuck-platesupport K, which swings on the rod J, the center of the chuck Otraveling in-the are m of a circle, as indicated in Fig. 4.

The grinding mechanism consists, preferably, of a small electric motorDof the usual construction and operated in the usual manner, the shaft Dof which is provided at one end with a grinding-wheel d and at the otherend with a polishing-wheel d. This motor is pivotally mounted upon abase D operating on the ways A so that it can be adjusted toward or awayfrom the chuck O and can be swung around on its pivotal hearing, so thateither the grinding-Wheel d or the polishingwheel 01' can be used, asdesired.

I have thus shown and described a convenient mechanism embodying myinvention,and the operation of this mechanism is as follows: The glass Pto be ground is secured to the face of the chuck O by means of adhesivematerial or in other convenient manner. The ratchet-nut L is thenadjusted to its innermost position on the rod J, which operates to movethe arms J J and the lens-chuck support along the rod J, so as tocompress the springJ ThesleeveEsupportingthe spherical bearing G, isthen moved along the rod or bar 13 to such point as will determine thefocal distance of the first field to be ground upon said glass P, andthe clutch H is then secured to the shaft I. The grinding-wheel cl isthen adjusted to operate on the glass P and the mechanism started. Theoscillating motion of the shaft I-I operates, through the belts 72 7tand through the intermediate mechanism hereinbefore described, to give agyrating motion to the lens-chuck during its oscillation back and forththrough the arc of a circle of approximately ninety degrees. Meanwhilethe operation of the ratchet mechanism on the nut L operates to unscrewit, allowing the spring J to impart a lateral motion to the lens-chucksupport K, swinging upon the rod J and carrying the glass in front ofthe grinding-wheel (l, and as it travels in this manner past thegrinding-wheel one portion of the lens is ground for one focal distance,and after this is completed the chuckplate M is adjusted by means of thescrews 2' i and the slots mm, and the sleeve F and mechanism supportedthereby are adjusted to the proper focal distance of the other field tobe ground on the glass P and the clutch II again secured to the shaft I,when the grindingwheel 61 operates to grind the remaining portion of thelens for the other focal distance upon said glass.

The polishing is accomplished by the use of the polishing-wheel d in thesame Way as in the grinding hereinbefore described, which operationsadapt this machine to produce the bifocal lenses illustrated in Figs. 7and 8.

I have thus described the construction and operation of a machine forgrinding bifocal lenses embodying my invention, so as to en* able othersto utilize the same; but I do not desire to limit myself to the exactconstruction hereinbefore shown and described, as many modifications ofthe construction thereof can be readily made by those skilled in the artto which this invention appertains without departing from the spirit ofsaid invention. Therefore What Iclaim as new, and desire to secure byLetters Patent of the United States, is-

1. The combination in a machine for grinding bifocal lenses, of alens-chuck having a simultaneous gyrative and transversemotion, and agrinding mechanism adapted to oper ate on a glass secured to said chuck,substantially as and for the purpose set forth.

2. The combination in a machine for grinding bifocal lenses, of alens-chuck, mechan ism forimparting gyratin g and transverse mo tion tosaid lens-chuck, and grinding mech anism adapted to be adjusted towardand away from said lens-chuck, substantially as and for the purpose setforth.

3. The combination in a machine for grinding bifocal lenses, of a1ens-chuck, mechananism for imparting a gyrating motion to said' chuck,means for adjusting the amount of the gyrative motion of the lens-chuck,mechanism for moving the lens-chuck support transversely back and forth,and grinding and pol-' ishing mechanism adapted to operate on a glasssecured to the lens-chuck, substantially as and for the purpose setforth.

l. The combination in a machine for grinding bifocal lenses, of alens-ohuck-supporting mechanism, a lens-chuck adj ustably mountedthereon, oscillating shaft and yoke mechanism adapted to rotate saidlens-chuck mechanism simultaneously with the transverse movement of saidchuck, a longitudinally-adjustable ball-and-sleeve bearing for the rearend of said oscillating shaft, clamp mechanism for securing said sleeveto said shaft, reversible mechanism for moving the lenschuck supportingmechanism transversely back and forth, and grinding mechanism adapted tobe adjusted to operate on a glass secured to said lens-chuck,substantially as and for the purpose set forth.

5. The combination in a machine for grinding bifocal lenses, of alens-chuck support H.. E. FISH, KARL W. SOHUUR.

